leetcode.com 202. Happy Number

main.go

func isHappy(n int) bool {
    if n <=0 {
        return false
    }
    used := make(map[int]bool)
    used[n] = true
    for n!=1 {
        fmt.Println(n)
        k:= n
        sum := 0
        for k>0 {
            w:=k%10
            k = k/10
            sum +=w*w
        }
        if _, ok := used[sum]; ok {
            return false
        }
        used[sum] = true
        
        n = sum
    }
    
    return true
}